It must be a soft launch for institutional investors first. Their site still says invite only.
We have begun sending out invite codes so you can create and fund your account in preparation for trading, which officially begins on Thursday, October 8th at 9:30 AM EDT. If you havent done so already, you can request an invite code by clicking Get Early Access on the Gemini homepage.
https://blog.gemini.com/and-were-live/#more-31